Series connected circuits containing lighting sources are well known especially in lighting strings and flexible lighting (Rope Lights) around the holidays when such light strings are used for decorative purposes. More recently, series connected lighting sources are becoming popular in task lighting, general illumination, automotive lighting, and specialty lighting utilizing LEDs. Generally, the lights in these lighting circuits are electrically in series rather than in parallel. One particular drawback to these types of lighting circuits is that when a lighting source is removed from the circuit, is burnt out, defective, or has a loose connection, the entire lighting circuit is rendered inoperable. Each lighting element within the circuit completes the electrical circuit, so when a light source is removed (for a replaceable type), a connection becomes loose, or the lighting element burns out or other lighting component within the light source, a gap is created in the circuit and electricity is unable to continue to flow through the circuit. When a “good” light source is inserted into the circuit or socket, it completes the circuit, thus allowing electricity to flow uninterrupted.
Specifically, Fisherman, U.S. Pat. No. 2,760,120, discloses a series circuit for a light set with individual incandescent flasher or twinkle bulbs that include a bypass resistor in parallel with the bulb element. The operation of the Fisherman light set is limited to a set with a bulb that flashes on and off, a duty cycle of less than 100%. The on time of the bulb is necessary to control heat generation in the resistor, the resistor conducting during the off time of the bulb, thereby regulating the heat produced in the resistor circuit. The Fisherman device cannot be applied to a set wherein a bulb is burnt out, removed, or loose (and not conducting) to continue to illuminate the remaining bulbs in the circuit. In such situation, the bypass resistor is continually conducting and the temperatures generated on any bypass resistor of practical size (let alone one that fits into a socket) will far exceed ignition temperatures of near by materials used in construction of the set. Further, the Fisherman bulb is a high energy bulb, being 8 volt and ¼ amp, for a power consumption of 2 watts. A more energy efficient bulb is in demand at the present time. Presently, bulbs, such as that depicted generally at 500 in prior art FIG. 15, are utilized. Such bulbs are a considerable improvement when compared to the Fisherman bulb, having 0.35-0.425 watt power consumption. There is still a need in the industry for a more energy efficient bulb.
While previous mechanical and electrical circuit configurations have been used in an attempt to address the problems described above, none do so with the reliability, simplicity, low cost of the present invention, and reduced energy consumption. The difficulties and drawbacks of previous lighting series circuit configurations are overcome by the resistive bypass for a series light circuit of the present invention.